In a disc drive system, air currents are induced when one or more discs are rotating at high speeds. Air currents, or windage, cause undesirable effects, such as vibration in system components. Such vibration is undesirable because it can introduce errors in the performance of the disc drive. One component that is adversely affected by this windage-induced vibration is the suspension assembly. The suspension assembly is used to support/suspend a read/write head, and is mated with an interconnect assembly, which is used to electrically connect the read/write head to disc drive electronics that are positioned away from the read/write head and off the suspension assembly.
One type of interconnect assembly is a flex-on suspension, or flex circuit. Flex circuit interconnect assembly includes a separately fabricated printed circuit that is typically mounted to the suspension assembly using an adhesive after assembly of the other suspension components. The flex circuit is relatively less expensive and easier to manufacture than the other types of interconnect assemblies.
Other types of suspension interconnect assemblies include twisted wires, trace suspension assemblies, and circuit integrated suspension assemblies. Twisted wire assemblies include a bundle of wires that are glued to the suspension assembly. A trace suspension assembly includes a unitary steel gimbal with electrical traces welded to the suspension assembly. A circuit integrated suspension assembly deposits traces directly onto the suspension assembly by a sputtering or like deposition process.
In general, the flex circuit is mated to a finished suspension assembly. The flex circuit is compliant along its entire length. The head and center portions of the flex circuit are typically attached to the suspension. However, the tail portion of the flex circuit is generally not attached to the suspension and hangs freely or is attached with tabs extending outward from a side of the suspension along a length of the base plate of the suspension. Thus, the tail portion is typically susceptible to windage forces present in the disc drive assembly that then translates to undesirable vibrations in the suspension assembly.
As the data density on the disc is continually increasing, it becomes more critical to eliminate or reduce factors that introduce error into the head reading and writing data. Since vibration of the suspension assembly is one factor that affects the operation of the head, a need exists for reducing windage-induced vibration of the head caused by the suspension assembly.